Introduction Faecal calprotectin (FC) has become a useful marker of mucosal healing, with studies showing raised levels predictive of relapse1,2,3. These studies did not assess mucosal healing however, so did not compare calprotectin with mucosal appearance as predictors of relapse.
Methods In the CODA (Colitis Once Daily Asacol®) trial of once daily (OD) Asacol® (three 800 mg tablets) vs one 800mg tablet taken three times daily (TDS), 213 UC patients in remission for >4 weeks, but relapse in the past 2 years, were recruited. Baseline FC (Phical ELISA kit) was collected and rectal sigmoidoscopy (sig) score at baseline, and relapse or 1 year (using the modified Baron score: 0 = normal; 1 = erythema, decreased vascular pattern; 2 = marked erythema, absent vascular pattern, friability, erosions; 3 = spontaneous bleeding, ulceration). At entry patients had no symptoms of active disease, with a sig score of 0 or 1. Follow-up was for 1 year or until relapse (symptoms of active disease with a sig score of 2 or 3). Demographic factors, concomitant drugs, FC, sig score, CRP, and adherence were evaluated in a Cox regression model of time to relapse.
Results (Shown as median[IQR] unless stated otherwise). Remission duration prior to entry was 6.0 [3–12] months. Disease extent was extensive (30.0%), Lt. sided (54.9%), proctitis (13.6%). At entry FC was 78mg/kg stool [23.3–159.4], sigmoidoscopy score 0 (70.9%), 1 (29.1%). All were taking mesalazine, and 11.7% thiopurines. Baseline FC was higher if sig score was 1 (109[38–335]) than if 0 (62[21–120], p = 0.001, but did not differ according to disease extent or medication (including aspirin (n = 18) and occasional NSAIDs (n = 6). Remission rates at one year were 62% overall (68.9% in OD and 55.5% in TDS group). Factors associated with time to relapse were explored in a Cox proportional hazards model, with baseline FC dichotomised at 150mg/kg stool (as by Costa et al. Relapse risk was 2.5 times higher in those with baseline sig score 1 compared to score 0 (95% CI 1.32–4.76, p = 0.005). Age, concomitant medication, previous duration of remission, disease extent, smoking, trial medication adherence and baseline FC (cut off at 150 mg/kg stool or as a continuous variable) did not remain in the final model.
Conclusion In this study, sigmoidoscopy appearance at baseline was the sole factor predicting relapse over 1 year of maintenance mesalazine 2.4g, whereas calprotectin level was not a predictor, perhaps because of wide variability in this group of patients. FC may have more value in measuring relative change in individual patients.
Disclosure of Interest A. Hawthorne Grant/Research Support from: CODA study supported by unrestricted grant from Warner Chilcott, D. Gillespie: None Declared, C. Probert: None Declared
Gisbert IBD 2009; 15:1190.
Tibble Gastroenterol 2000; 119:15.
Costa Gut 2005; 54:364.
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